Side Effects

Along with their needed effects, thioxanthenes can sometimes cause serious side effects. Tardive dyskinesia (a movement disorder) may occur and may not go away after you stop using the medicine. Signs of tardive dyskinesia include fine, worm-like movements of the tongue, or other uncontrolled movements of the mouth, tongue, cheeks, jaw, or arms and legs. Other serious but rare side effects may also occur. Some of these side effects, including severe muscle stiffness, fever, unusual tiredness or weakness, fast heartbeat, difficult breathing, increased sweating, loss of bladder control, and seizures, may be the sign of a condition called neuroleptic malignant syndrome. You and your doctor should discuss the good this medicine will do as well as the risks of taking it.

Although not all of these side effects may occur, if they do occur they may need medical attention.

Stop taking this medicine and get emergency help immediately if any of the following effects occur:

Rare

Convulsions (seizures)

difficulty in breathing

fast heartbeat

high fever

high or low (irregular) blood pressure

increased sweating

loss of bladder control

muscle stiffness (severe)

unusually pale skin

unusual tiredness

Check with your doctor as soon as possible if any of the following side effects occur:

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Constipation

decreased sweating

dizziness, lightheadedness, or fainting

drowsiness (mild)

dryness of mouth

increased appetite and weight

increased sensitivity of skin to sunlight (skin rash, itching, redness or other discoloration of skin, or severe sunburn)

stuffy nose

Less common

Changes in menstrual period

decreased sexual ability

swelling of breasts (in males and females)

unusual secretion of milk

After you stop taking this medicine your body may need time to adjust, especially if you took this medicine in high doses or for a long time. If you stop taking it too quickly, the following withdrawal effects may occur and should be reported to your doctor:

Although not all of the side effects listed above have been reported for all thioxanthenes, they have been reported for at least one of them. However, since these medicines are very similar, any of the above side effects may occur with any of them.

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.